﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace machine_registration.Services
{
    internal class Dormancy
    {/// <summary>
     /// 包含控制屏幕关闭以及系统休眠相关的方法。
     /// </summary>
        public static class SystemSleep
        {
            [DllImport("kernel32")]
            private static extern ExecutionState SetThreadExecutionState(ExecutionState esFlags);
            [Flags]
            private enum ExecutionState : uint
            {
                /// <summary>
                /// Forces the system to be in the working state by resetting the system idle timer.
                /// </summary>
                SystemRequired = 0x01,

                /// <summary>
                /// Forces the display to be on by resetting the display idle timer.
                /// </summary>
                DisplayRequired = 0x02,

                /// <summary>
                /// This value is not supported. If <see cref="UserPresent"/> is combined with other esFlags values, the call will fail and none of the specified states will be set.
                /// </summary>
                [Obsolete("This value is not supported.")]
                UserPresent = 0x04,

                /// <summary>
                /// Enables away mode. This value must be specified with <see cref="Continuous"/>.
                /// <para />
                /// Away mode should be used only by media-recording and media-distribution applications that must perform critical background processing on desktop computers while the computer appears to be sleeping.
                /// </summary>
                AwaymodeRequired = 0x40,

                /// <summary>
                /// Informs the system that the state being set should remain in effect until the next call that uses <see cref="Continuous"/> and one of the other state flags is cleared.
                /// </summary>
                Continuous = 0x80000000,
            }
            /// <summary>
            /// 设置此线程此时开始一直将处于运行状态，此时计算机不应该进入睡眠状态。
            /// 此线程退出后，设置将失效。
            /// 如果需要恢复，请调用 <see cref="RestoreForCurrentThread"/> 方法。
            /// </summary>
            /// <param name="keepDisplayOn">
            /// 表示是否应该同时保持屏幕不关闭。
            /// 对于游戏、视频和演示相关的任务需要保持屏幕不关闭；而对于后台服务、下载和监控等任务则不需要。
            /// </param>
            public static void PreventForCurrentThread(bool keepDisplayOn = true)
            {
                SetThreadExecutionState(keepDisplayOn
                    ? ExecutionState.Continuous | ExecutionState.SystemRequired | ExecutionState.DisplayRequired
                    : ExecutionState.Continuous | ExecutionState.SystemRequired);
            }

            /// <summary>
            /// 恢复此线程的运行状态，操作系统现在可以正常进入睡眠状态和关闭屏幕。
            /// </summary>
            public static void RestoreForCurrentThread()
            {
                SetThreadExecutionState(ExecutionState.Continuous);
            }

            /// <summary>
            /// 重置系统睡眠或者关闭屏幕的计时器，这样系统睡眠或者屏幕能够继续持续工作设定的超时时间。
            /// </summary>
            /// <param name="keepDisplayOn">
            /// 表示是否应该同时保持屏幕不关闭。
            /// 对于游戏、视频和演示相关的任务需要保持屏幕不关闭；而对于后台服务、下载和监控等任务则不需要。
            /// </param>
            public static void ResetIdle(bool keepDisplayOn = true)
            {
                SetThreadExecutionState(keepDisplayOn
                    ? ExecutionState.SystemRequired | ExecutionState.DisplayRequired
                    : ExecutionState.SystemRequired);
            }
        }
    }
}
